Studies will continue to be concentrated on genetic regulatory mechanisms in the qa gene cluster. Recent experiments have succeeded in constructing a recombinant E. coli plasmid in which the qa-2 gene product, catabolic dehydroquinate, is expressed. Additional studies will be required to determine whether any other genes of the cluster are present in the plasmid. This information will be of major importance in determining the molecular mechanisms operating in regulating the induction of the three enzymes encoded in the qa gene cluster. This system should make possible the isolation of specific qa DNA and mRNA, and to employ the latter in an already developed in vitro system for translating Neurospora mRNA. Studies will also continue on the purification and characterization of the three enzymes encoded in the qa gene cluster. BIBLIOGRAPHIC REFERENCES: Case, Mary E., Judith A. Hautala, and N. H. Giles. 1977. Characterization of qa-2 mutants in Neurospora crassa by genetic, enzymatic, and immunologic techniques. J. Bacteriol. 129: 166-172. Hautala, J.A., B.H. Conner, J. W. Jacobson, G. L. Patel, and N. H. Giles. 1977. Isolation and characterization of nuclei from Neurospora crassa. J. Bacteriol. (in press).